Question

A typical red blood cell subtends an angle of only 2.0�10?5rad when
viewed at a person's near-point distance of 25cm . Suppose a red
blood cell is examined with a compound microscope in which the
objective and eyepiece are separated by a distance of 12.0cm
.

Given that the focal length of the eyepiece is 3.0cm , and the
focal length of the objective is 0.49cm , find the magnitude of the
angle subtended by the red blood cell when viewed through this
microscope.